Ky Grady said:
I have the boat pictured in my signature. A 2004 228 with a F225. I'm running a Power Tech OSF4, 15 1/4 x 16, which is a four blade. My prop that was on my boat when I got it was a 15 1/4 x 17, 3 blade. It did ok, but getting the 4 blade was a big difference.
2 people, 56 gal of fuel, 6100rpm, 41-42mph. WOT
Love this prop, lifts the stern and keeps me on plane at a slower speed, very little, if any loss on top end. Great mid range performance. Pretty decent hole shot getting up on plane with the F225.
These boats are heavy and this prop does very well. The F225 is not known as a powerhouse motor as far as umph. The four blade helps compensate for that and this motor/prop combo works well on my 228.
I went through Ken at PropGods for the prop. Very knowlegeable guy. Perfect recommendation for a prop.
Assuming I have the correct gear ratio for that motor (2.0) your specs are excellent, perhaps better than I would expect especially with the load mentioned. If you are making 42mph at WOT your slip is small, about 7%.
Being from NY, I am a bit skeptical
I also see that the WOT range for that motor is 5000 to 6000 so you are close to over revving but you probably don't run at 6100 a lot.
In general a 4 blader should be sized an inch smaller than a 3 blade prop. In that case, the equivalent 3 blade prop would be 15 1/4 by 17.
Is your hull painted?
I also agree with the post that said that something is wrong with the original poster's top end of 4200 revs. Before investing in a new prop, I would find out what is going on. It could be a damaged prop, a slipping prop, a fuel starvation issue or some other electronic problem.